The objective of the proposed study is to examine longitudinally the early developmental antecedents of individual differences in self-control among preschool children. The self-control capabilities of 106 6-year-old children will be assessed using a combination of teacher report, parent report, observational and structured laboratory techniques. Extensive, detailed longitudinal data on the parent-child interaction, temperamental, and cognitive competence characteristics of these same children was collected during an earlier research project. These early assessments were conducted when the children were 6, 13, and 24 months of age. The existence of these data provides a unique opportunity to study the developmental antecedents of an important clinical problem: the emergence of behavior problems reflecting self-control deficits. Once the proposed self-control assessments have been completed, interrelations between different concurrent measures of children's self-control will be examined, to see if subtypes of selfcontrol problems can be reliably identified. Multivariate statistical methods will then be used to identify specific types and/or combinations of parent-child interaction, child temperament, and child cognitive competence variables which best predict self-control problems vs. competence at age 6. Since so little is known about the development of self-control problems, the results of the present study will help fill a significant gap in the child development and clinical literature. The results of the proposed study will also be highly relevant to questions concerning the etiology of childhood behavior problems such as hyperactivity, and provide information useful for early identification efforts with children at risk for later self-control problems.